import cv2
cv2.namedWindow('color',cv2.WINDOW_NORMAL)

def callback():
    pass

img = cv2.imread('C:\\Users\\Mengyang\\Desktop\\Myopencv\\image\\112.png')

colorspaces=[cv2.COLOR_BGR2RGBA,cv2.COLOR_BGR2BGRA,
             cv2.COLOR_BGR2GRAY,cv2.COLOR_BGR2HSV,
             cv2.COLOR_BGR2YUV]
#BGR转RGB   BGR转BGR正常显示  BGR转灰度    转HSV   转YUV
cv2.createTrackbar('curcolor','color',0,len(colorspaces),callback)

while True:
    index = cv2.getTrackbarPos('curcolor','color')
    #颜色空间转换API
    cvt_img = cv2.cvtColor(img,colorspaces[index]) 
    cv2.imshow('color',cvt_img)
    key = cv2.waitKey(1)
    if key & 0xFF == ord('q'):
        break

cv2.destroyAllWindows()
